Audio Channel Reconstruction Using Direction Parameters
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Solution Overview
Problem
Current audio reproduction technologies struggle to effectively emphasize or enhance the direction of origin of audio signals during reproduction, especially in multi-channel setups, due to limitations in microphone directivity patterns and the need for specialized equipment and complex signal processing techniques.
Innovation Solution
A method and apparatus that select and modify audio channels based on direction parameters to increase the intensity of audio signals originating from a desired direction, allowing for enhanced directional perception and spatial reproduction, independent of the loudspeaker configuration, using a combination of direction selection and signal modification techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If narrow directional microphones are used to capture sound from specific directions, then spatial resolution and directionality are improved, but cost increases and frequency response quality degrades
Solution Approach 1:
The patent segments the audio signal processing into directional capture (recording phase) and directional enhancement (reproduction phase). During recording, omnidirectional microphones capture all sound. During reproduction, signal processing separates and enhances sounds from specific directions. This segmentation allows using inexpensive omnidirectional microphones while achieving directional audio reproduction.
Solution Approach 2:
The patent applies preliminary action by pre-processing the audio signal to extract directional information and store it with the audio data. Directional parameters are calculated and saved during recording, then used during reproduction to enhance specific directions without requiring specialized microphones at the reproduction stage.
2Measurement precision
If multiple loudspeakers are used to reproduce sound from multiple directions, then spatial impression is improved, but device complexity and setup requirements increase
Solution Approach 1:
The patent makes the audio reproduction system universal by creating directionally enhanced audio signals that can be reproduced on any loudspeaker configuration. The directional information is embedded in the audio signal itself, allowing the same processed signal to be played back effectively whether using one loudspeaker, two loudspeakers, or multiple loudspeakers in various configurations.
Solution Approach 2:
The patent changes the parameters of the audio signal by incorporating directional parameters (azimuth, elevation, distance) and applying directional weighting factors during signal processing. These parameter changes enable the audio signal to carry directional information that guides reproduction regardless of the physical loudspeaker arrangement.
3Ease of operation
If amplitude panning is used to distribute audio signals between loudspeakers, then spatial positioning is achieved, but directional precision and flexibility are limited
Solution Approach 1:
The patent extends simple amplitude panning by introducing additional parameters beyond amplitude: azimuth angle, elevation angle, and distance. These parameters enable precise three-dimensional directional positioning. The system calculates directional weighting factors based on these parameters, providing much finer control over spatial positioning compared to traditional two-channel amplitude panning.
Solution Approach 2:
The patent transitions from two-dimensional amplitude panning (left-right distribution) to three-dimensional directional control by adding elevation and distance dimensions. This allows audio sources to be positioned not only left-right but also in terms of height and distance, creating more precise and realistic spatial imaging.
Data Source
AI summary
An audio signal having at least one audio channel and associated direction parameters indicating a direction of origin of a portion of the audio channel with respect to a recording position is reconstructed to derive a reconstructed audio signal. A desired direction of origin with respect to the recording position is selected. The portion of the audio channel is modified for deriving a reconstructed portion of the reconstructed audio signal, wherein the modifying includes increasing an intensity of the portion of the audio channel having direction parameters indicating a direction of origin close to the desired direction of origin with respect to another portion of the audio channel having direction parameters indicating a direction of origin further away from the desired direction of origin.